Also found in: Acronyms.
built-up roofing[′bilt‚əp ′rüf·iŋ]
A seamless piece of flexible, waterproofed roofing material consisting of plies of felt mopped with asphalt or pitch.
Flat roof covered with multiple layers of roofing felt, secured with layers of hot tar, and topped with a layer of crushed stone. See also: Roof